1. Field of the Invention
The present invention relates generally to arrangements for forming automobile cowl structures, and more particularly, to an arrangement for forming a cowl portion of an automobile body by which a sight point at the lower portion of a front windshield is set to be low so that the forward visibility for driving in an automobile is improved.
2. Description of the Prior Art
In an automobile body, a cowl structure located in front of a cabin space is usually provided with a ventilation device which is operative to introduce fresh air into a blowing duct opening to the cabin space for air conditioning. There has been proposed one of such ventilation devices which has a natural ventilation duct with its inlet end disposed at the rear portion of a cowl structure to take fresh air therein, as desclosed in the Japanese patent specification published before examination under the publication number: 59-53112.
FIG. 1 shows a part of an automobile body construction to which a previously proposed cowl structure accompanied with a ventilation device of the aforementioned type is adapted. In the automobile body construction shown in FIG. 1, an air conditioning unit 1 is contained in a space formed by a lower dash panel 2, an upper dash panel 3 and other members to supply warm air or cool air to a cabin space 5 through a ventilation duct 4. A natural ventilation duct 6 is mounted to pass through the rear wall portion of the upper dash panel 3 with its inlet end 7 opening into a space 9 in a cowl portion 8 for taking fresh air therein. The fresh air taken into the natural ventilation duct 6 through the inlet end 7 thereof is guided into the ventilation duct 4 to be mixed with the warm air or cool air supplied therethrough to the cabin space 5. The space 9 is formed with a front cowl panel 10, the upper dash panel 3, a cowl cover panel 11 and a cowl top member 12 both mounted on the upper dash panel 3 and so on. In addition, an engine bonnet 14 accompanied with a reinforcing member 13 is provided to face the front cowl panel 10 with a seal member 15 between for covering an engine and other equipments.
A windshield supporting frame 16 composed of the cowl cover panel 11 and the cowl top member 12 is shaped to extend along a front windshield 17 and the lower end of the front windshield 17 is attached through an adhesive 18 to a front surface 16a of the windshield supporting frame 16. Further, an instrument panel 19 is provided in the cabin space 5 to cover the windshield supporting frame 16, the rear wall portion of the upper dash panel 3, the natural ventilation duct 6 and the ventilation duct 4. A horizontally extending portion 19A of the instrument panel 19 is positioned to be at the same level as a rear end portion 14a of the engine bonnet 14.
In connection with such a previously proposed automobile body construction, it has been recently desired to lower a sight point 23 at the lower portion of the front windshield 17 in order to realize such a body shape as reduced in height and improved in forward visibility. However, in fact, since the windshield supporting frame 16 is disposed on the natural ventilation duct 6, the horizontally extending portion 19A of the instrument panel 19 is inevitably positioned at a relatively high level and therefore the rear end portion 14a of the engine bonnet 14 is also positioned at the relatively high level, so that the sight point 23 at the lower portion of the front windshield 17 is set to be relatively high.
For lowering the sight point 23, it is considered to reduce the height of the lower dash panel 2. However, it is quite difficult to make the lower dash panel 2 low because the air conditioning unit 1 is provided under the lower dash panel 2 and a transmission unit may be disposed further under the air conditioning unit 1. Besides, a floor in the cabin space 5 is connected to the lower dash panel 2 in such a manner that an appropriate space for legs of a driver is provided on the floor, and consequently the lower dash panel 2 must be relatively high in its height.
In addition to the above mentioned problem, there is a further disadvantage in the previously proposed automobile body construction as follows. The natural ventilation duct 6 is mounted to pass through the rear wall portion of the upper dash panel 3 as described above and therefore it is feared that the lower part of a mounting portion of the natural ventilation duct 6 engaging with the upper dash panel 3 is soaked in rainwater or washing water collected on the bottom of the cowl portion 8. Accordingly, a tight seal member 20 must be placed between the rear wall portion of the upper dash panel 3 and the mounting portion of the natural ventilation duct 6 in order to prevent water collected on the bottom of the cowl portion 8 from entering or penetrating into the cabin space 5 through the natural ventilation duct 6.